virus (1) trajectoire (1) cheptel sur pied (1) santé animale (1) Causes (1) Costs (1) Antiquities, Prehistoric (1) Nineteen fifties (1) DNA, Fossil (1) Genes (1) Animal health (1) Tumors (1) Science (1) Pathogenic microorganisms (1) Medicine (1) Marek's disease (1) Prehistoric peoples (1) Livestock (1) Growth (1) Genomes (1) Example (1) Driving of horse-drawn vehicles (1) Chickens (1) Birds (1) Tumors (1) Pathogens (1) Medicine (1) Infections (1) Growth (1)